Abstract
Aldosterone is synthesized in the adrenal zona glomerulosa via the action of the mitochondrial cytochrome P450 enzyme aldosterone synthase (CYP11B2) through sequential enzyme reactions. Pathogenic variants in CYP11B2 result in corticosterone methyloxidase type I deficiency (CMO I), an orphan condition with a potentially lethal electrolyte imbalance in infancy. We report the unique occurrence of CMO I with celiac disease in the first genetically confirmed Polish case of CMO I; a 15-year-old female, diagnosed initially in the neonatal period because of severe hyponatremia, hyperkalemia, metabolic acidosis, and failure to thrive. The patient's clinical course was complicated by protracted electrolyte abnormalities, poor weight gain, and eventual diagnosis of celiac disease, which temporally correlated with abnormal growth patterns. Extensive endocrine assessment, steroid profiling, and next-generation DNA sequencing revealed a homozygous pathogenic variant in CYP11B2 (c.1354G>A; p.Gly452Arg), confirming CMO type I.